1. Field of the Invention
The present invention relates to a tinnitus rehabilitation device and a method for providing relief and treatment to persons suffering from the disturbing effects of tinnitus. More particularly, though not exclusively, the present invention relates to such a method and device that employs intermittent masking of the tinnitus.
2. Description of Related Art
Tinnitus is the perception of a sound in the absence of any corresponding external sound. It is most commonly perceived as a ringing, buzzing, whirring type sound, but can also be perceived as a beating, or pounding sensation. Approximately one third of the people who suffer from tinnitus can be highly disturbed by it. Continuous perception of tinnitus can lead to insomnia, an inability to relax, state and trait anxiety, depression, and even suicide in extreme cases. Often closely associated with tinnitus is the perception of hyperacusis, which is a great intolerance to external sounds, even the softer everyday sounds. This distressing condition can even occur as a precursor to tinnitus, and is thought to share the same underlying causes. Thus, every reference to tinnitus in this document should be construed as including the phenomena of hyperacusis or other types of loudness discomfort.
There are very few effective treatment options available for tinnitus sufferers, with the vast majority only being advised that “you'll have to learn to live with it”. Most patients find that they can far more readily ignore an external sound than their tinnitus. One palliative method has been to use hearing aid-style devices that produce a band of noise to totally mask the perception of the tinnitus. A variety of such devices have been described, including a tinnitus masker that produces sounds of from 1,000 Hz to 5,000 Hz (U.S. Pat. No. 4,222,393), a patient-controlled master hearing aid (U.S. Pat. No. 4,759,070), a masker that produces a sound spectrum containing a line spectrum with a fundamental tone that is adjustable from 125 Hz to 20,000 Hz (U.S. Pat. No. 5,167,236), a masker whose output slowly cycles through a frequency range (U.S. Pat. No. 5,325,827), a masker with a bandwidth selector function (U.S. Pat. No. 5,403,262), a masker comprising a frequency response analyzer and shaping apparatus (U.S. Pat. No. 5,663,727). Such masking can give a sense of relief and control over the tinnitus in up to half of patients, but usually has no long-term effect. The prohibitive cost and aesthetic considerations limits the proportion of sufferers for whom this is a viable measure. The presence of hearing loss for external sounds in the tinnitus region often means that the masking noise needs to be unpleasantly loud before the tinnitus can be masked, and the noise is often judged to be not much better than the tinnitus itself.
Other reported devices attempt to achieve masking using devices that deliver vibrations (U.S. Pat. No. 5,692,056), pulsed ultrasonic stimulation (U.S. Pat. No. 6,394,969) or radio frequency waves (eg. “Theraband.™”) to the patient, while other reported devices (eg. U.S. Pat. No. 5,697,975) seek to achieve stimulation through direct electrical discharge to the brain. Yet another seeks to provide relief by delivering an acoustic stimulus at a level that is inaudible to the patient (PCT WO 0170110).
Over the past decade, a new understanding of the neurophysiological processes underlying tinnitus has been published, emphasizing the role of the neural pathways in the emergence of distressing tinnitus and the possibility of using this neural plasticity to retrain its perception. This has been dubbed “Tinnitus Retraining Therapy” or TRT. In this technique, patients are given intensive counseling, and use noise generators at a volume that does not completely mask the tinnitus. Long term reductions in tinnitus disturbance have been achieved in some patients, but it is usual for this process to take at least 18 months of therapy before any substantial benefit occurs. TRT also offers very little immediate sense of relief from the tinnitus, and no relief from the associated sleep disturbance and inability to relax.
The closest known prior art to the invention is the “Silentia Set” developed by Starkey Corp., which is a pair of hearing aid devices which wirelessly receive signals from a stereo system via an induction loop under a pillow at bedtime. Recording of high frequency noise bands (“water sounds”), babble noise, traffic sounds and music have been used to mask tinnitus using this system, however the high cost of the Silentia Set make it prohibitive for many sufferers.
Other prior art audiotherapeutic techniques using music are the Tomatis Method developed by Alfred A. Tomatis, and Auditory Integration Training. While neither method is designed for the treatment of tinnitus, the two techniques have some similarities in that they modify music for the treatment of auditory disorders. The Tomatis Method employs an “Electronic Ear” developed by Alfred Tomatis, (U.S. Pat. No. 4,021,611). It has its origins from an extremely outdated model of how the auditory system works, and has been widely debunked by audiological organizations. Auditory Integration Training is based on the Tomatis Method, but presents the music at extremely loud levels, that may result in hearing damage, and importation of devices using this technique have been banned by the American Food and Drug Administration.